The study focuses on an analysis of the writings of social workers’, published in two Finnish professional journals of social work, from 1990 to 1997. The aim is to study the ways of how social workers categorize uncertainty and professional tensions of social work, due to the socio-cultural changes in Finland during the 1990s. The research method for this study is based on a categorization analysis inspired by (1) the concept of “category” by Aristotle; (2) the issues of discourse analysis in general; and (3) MCD, originally developed by Harvey Sacks in the 1960s and 1970s. The basic concept of this study – “categorization” – refers to two different forms of written representation by social workers.In representations on ‘the politics of uncertainty’, social workers raise up three issues. They emphasize that the recession of the 1990s left certain marks on the Finnish society and, thus, also on social work. They see that job description has totally changed in the 1990s and become more challenging and demanding. They believe that the conflicts between decision-makers and social workers produce a natural uncertainty in social work. In representations on ‘professional tensions’, social workers address three main problems. They think that the relationship between client and worker creates a fundamental tension in social work practice. They regard burnout in work as a hassle for many frustrated and stressed workers. They argue that the difficulties to define the limits of responsibility and power are due to the situation in which workers are both professionals in natural responsible positions, and indisputable experts in power based on their professional status